Low-mass stars in the massive HII region NGC 3603 - Deep NIR imaging with ANTU/ISAAC

We have observed NGC 3603, the most massive visible H II region known in th e Galaxy, with ANTU(VLT1)/ISAAC in the near-infrared (NIR) J(s), H, and K-s -bands, Our observations are the most sensitive observations made to date o f this dense starburst region, allowing us to investigate with unprecedente d quality its low-mass stellar population. Our mass limit to stars detected in all three bands is 0.1M. for a pre-main sequence star of age 0.7 Myr. T he overall age of the pre-main sequence stars in the core region of NGC 360 3 has been derived from isochrone fitting in the colour-magnitude diagram, leading to 0.3-1.0 Myr. The NIR luminosity functions show that the cluster is populated in low-mass stars at least down to 0.1M.. Our observations cle arly show that sub-solar mass stars do form in massive starbursts.